mysterious delay lines

[Frank Lemieux]

Looking through my bin of mysterious surplus parts, I've found these
oddities: little plastic rectangles marked "delay line".  

The symbol upon these is a diamond, with "KSS" inside.  They model numbers
at MS-15 and MS-19.  There are 4 leads coming out the bottom.

Anyone have any data on these things?  If they are what I think they are,
they have a million uses...

-/9\-